Such a method is known from EP-B 0 133 239, in which pressure and temperature are held constant during the holding phase, in order to allow the desired reaction to proceed during this time. There then follows a drying process in an intermediate phase, during which the autoclave is additionally heated more than to compensate for heat losses and to a temperature above the temperature of vaporisation of the water, so that excess water in the goods is partially vaporised and discharged as steam, in order to obtain a dry product at the end of the autoclave cycle. However, primary energy is used in this both for the heating up and for holding and drying--this involving a corresponding additional invested expense.
The object of the invention is to teach a method of the kind initially referred to, which makes it possible to carry out the drying process without taking up additional time and without the contribution of additional primary energy.